Ordnance breech mechanism



March 29, 1927. Y 1,622,861

A. T- DAWSON ET AL oRDNANCE BREECH MECHANISM Filed Aug.25. 1926 5Sheets-Sheet 1 March 29 1927.

A. T. DAWSON ET AL ORDNANCE BREECH MECHANISM Filed Aug 25 1926 5A'Sheets-Sheet a mdwnmw:

A. T DAWSON ET AL ORDNANCE BREEGH MECHANISM Filed Aug.25. 1926 3Sheets-Sheet 3 Patented Mar. 29, 1927.

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ARTHUR TREVOR DAWSON AND GEORGE THOMAS BUCKI-IAM, OF WESTMINSTER, LON-DON, ENGLAND, ASSIGNORS T0 VICKERSLMITED, OF WESTMINSTER, LONDON;

ENGLAND.

Application filed August 25, 1926, Serial No. 131,491), and. in GreatBritain` September 16, 1925.

This invention relates to breech mechanism of the vertically slidingblock type for semi-automatic guns convertible at will into quick-tiringguns, such breech mechanism having a spring which is energized duringthe automatic opening of the breech in semiautomatic operation andserves to close the breech when the gun has been re-loaded. For-handactuation of the breech mechanism (i. e. during quick-firing operation)the aforesaid spring is, in one known form of such breech mechanism,left in action so that the operato-r has to compress the spring duringthe opening of the breech by the operation of the breech actuating handlever, which operation is rendered difficult owing to the strength ofthe spring, whilst in another known form of breech mechanism the springis disengaged for hand actuation in which case it is correspondinglydifficult to closer the breech owing to the Weight of the verticallysliding breech block.

According to the present invention in order to avoid the above-mentioneddiiiculties We provide two springs one of which is in action during boththe semi-automatic and the quick-firing operations and which is of suchystrength as to balance or approximately balance the weight of thebreech block, and the second spring is in action together with theformer .spring during semiautomatic operation onlv, this second springbeing disconnected during quick-tiring operation. Thus duringsemi-automatic operation there are two springs in action (which springscombined serveA the purpose of the single spring heretofore employed)and during quick-tiring operation there is only one spring in actionwhich serves to balance or approximately balance the weight of thebreech block so that the latter can be operatedA easily by hand. Inorder to differentiate these springs we will hereinafter refer to thespring that is in action during both the semi-automatic and thequick-firing operations as the balancing spring and the spring that isin operation together with the balancing spring during semi-automaticoperation as the main closing spring. The said balancing spring may bearranged longitudinally at the side of the gun opposite to that Wherethe breech actuating hand lever is situated and may be compressed by arack transversely at the lower part of the breech ring and is operatedautomatically on the run-out movement of the gun to open the breechduring semi-automatic operation, and the main closing spring may becarried by the breech actuating hand-lever Which,l during semi-automaticoperation, is connected to the gun and disconnected from the breechactuating crank shaft and which] during quick-firing operation isdisconnectedr from the gun and connected to the said crank shaft, theconnecting and disconnecting being effected by spring-controlled catchesoperated simultaneously When the operator grasps the handle of thebreech actuating hand-lever; the said main closing spring in the formeror semi-automatic condition is compressed bv a rack member operated Lbya pinion on the crank shaft as is Well understood and moves With thebreech actuating hand-lever in the other .or quick-firing condition andis therefore not energized during this operation.

In order that the said inventionv may be clearly understood and readilycarried into effect, the same will noW be described more fully withreference to the'accompanying drawings in Which:-

Figure l is a rear elevation of the breech end of a gun provided withour improvements, p

Figure 2 is a plan of vFigure l,

Figure 3 isa side elevation of Figure 1 as viewed from the left of thelatter ligure,

Figure 4 is a side elevation of Figure 1 as fiewed from the right of thelatter ligure, an

Figure 5 is a section taken approximately on the line 5, 5 of Figure 4c.

A is the breech ring of the gun, B is the vertically sliding breechblock, C is the breech actuating hand-lever arranged at the right-handside of the gun with the handle uppermost, D is the transverse breechactuating crank shaft which passes through the lower part of the breechring and to the right-hand end of which the hand-lever C can beconnected in the manner hereinafter described, this shaft operating thebreech block B in any known lor desired manner. E is the aforesaidbalancing spring arranged longitudinally in a. recess in the left-handside of the breech ring A and F is the aforesaid main closing springcarried by the breech actuating hand-lever C The balancing spring E isretained in position in its recess by a cap El and is operated upon by arack member E2 which engageswith a part pinion D1 attached to the breechactuating crank shaft D near the lefthandend thereof; consequently thisbalancing spring is compressed during the opening of thebr'eech'vrhether this opening is eiected by the hand-lever C duringquick firing operation, or whether it is effected automatically on therun-out movement of the gun during semi-automatic operation. Attached tothe breech actuating crank shaft D contiguous to the part pinion D1 is acrank D2 provided with a lateral pin or projection D3 for co-operatingwith curved or inclined operating surface on a pawl D4 pivoted t abracket on the cradle as is described in the specification of ourpatentapplication liled concurrently herewith. The said crank and pawlcould however be replaced by the usual cam and pawl. In either case thebreech actuating crank shaft D is operated to open the breechautomatically during the run-out movement of the gun and in so doing thebalancing spring E is compressed as is also the main closing spring F aswill now be described.

The said main closing spring F is carried in a recess in the breechactuating handlever C and is held in place by a cap F1. This spring actsupon a rack member F2 meshing with a part pinion D5 attached to theright-hand end of the breech actuating crank shaft D. In thesemi-automatic condition of the parts the breech actuating hand-lever Cis connected to the breech ring of the gun by means of a plunger C1(Figure 5) operated by one arm of a lever C2 the other arm of which isoperated upon by a spring C3 interposed between this arm and a catch Clforming part of a hand grip C5 which in the semi-automatic condition ofthe parts occupies the position shown in Figure 5 in which the catch C4is out of engagement with a. notch D6 in the part pinion D2. Under theseconditions, which are those occurring during semi-automatic operation,the spring F is compressed as well as the spring lE during the openingof the breech and both these springs are therefore operative in closingthe breech. For quick-firing operation the hand grip C5 is operated ingrasping the handle of the breech actuating hand-lever C and this causesthe catch C4 to engage with the aforesaid notch D6 of the part pinion D5and at the same time a pin C6 on a portion of the hand grip C5 rocks theaforesaid lever C2 in order to release the plunger C1 from engagementwith its notch in the breech ring,

.these .movements of the catch C* and the lever C2 compressing thespring Ci'. In this condition of the parts7 the hand-lever C isconnected to the breech actuating' crank shaft D and in opening thebreech by hand the aforesaid balancing spring E is alone B4 appertainingto the semi-automatic gear would be placed in the inoperative position.As the effective weight of the breech b lock tending to move it to theopen position 1s at the maximum when the gun is firing hori@ zontallyand is Zero when the gun is 'firing vertically, we preferably arrangedthe balancing spring E to be of such strength as to balance theelfective weight of the breech block at an angle of elevationintermediate between the two extremes for antiaircraft guns.

The lever C2 is provided with a projection C2x which extends through theside of the hand-lever C as shown. `This projection is for the purposeof liberating the plunger C1 from the gun in the event of the breechmechanism failing to close automatically. Under these circumstances thecatch C* is unable to rise and actuate the lever C2 as the head of thecatch is under the toothed portion of the part pinion` D5. When theplunger C1 is raised by pressing on the projection C2c the handlever Ccan be moved until the catch C2 reaches the position for engaging withthe notch D6 whereupon the breech mechanism can be closed by means ofthe said hand-lever.

lVhat we claim and desire to secure by Letters Patent of the UnitedStates is:

1. In ordnance breech mechanism of the vertically sliding block type forsemi-auto matic guns convertible at will into quickfiring guns, thecon'ibination of two springs one of which is in action during both thesemi-automatic and the quiclcfiring operations and which is of such astrength as to approximately balance the weight of the breech block, andthe second spring is in action together with the former spring duringthe semi-automatic operation only.

2. In ordnance breech mechanism of the vertically sliding block type forsemi-automatic guns convertible at will into quickfiring guns', thecombination with the transversely arranged crank shaft for operating thebreech mechanism by hand, and the hand-lever at one end of said crankshaft, of a spring arranged at the side of the gun opposite to thatwhere said hand-lever is situated, said spring being of such strength asto approximately balance the Weight of the breech block, means forenergizing said spring from said crank-shaft during the opening ot' thebreech mechanism during both the semi-automatic and the quick-firingoperation, a second spring carried by said hand-lever, and means forenergizing said second spring during the semi-automatic operation only.

3. In ordnance breech mechanism of the vertically sliding block type forsemi-automatic guns' convertible at will into quick- {iring guns, thecombination With the transyersely, arranged crank shaft for operatingthe breech mechanism `by hand, and the handlever at one end of saidcrank-shaft, of a spring arranged at the side of the gun opposite tothat Where said hand-lever is situated, said spring being of suchstrength as to approximately balance the Weight of the breech block,means for energizing said spring from said crank-shaft during theopening of the breech mechanism yduring both the semi-automatic and thequick-firing operations, a second spring carried by said hand-lever,means for connecting said 'hand-lever to the gim and disconnecting itfrom the crank-shaft during semi-automatic operation, a breech mechanismclosing spring carried by said hand-lever, and means for energizing saidspring from the crankvshaft during semi-automatic firing When thehand-lever is connected to the gun.

ARTHUR TREVOR DAWSON. GEORGE THOMAS BUOKHAM. i

